Sensor tilt would be very useful for setting the plane of best focus. Lens tilt is even better, but for most landscape applications, the distortion difference would probably not be important. I do not think getting back to the aligned setting would be much of a mechanical design challenge. And if tilt was off by a little bit, how would you notice? If you did notice, you would use the tilt function to correct it
One problem with sensor tilt is that light would no longer be hitting the pixels at normal incidence, so the micro-lenses in front of the pixels would be off-center, causing color fringing and various other problems. This is the same effect that already occurs at the edges of images captured using (non-telecentric) lenses not designed for use with digital sensors.